OAKLAND, Calif. (AP) — Complaints mounted about the cluttered warehouse converted into an illegal artists’ colony before a deadly blaze ripped through earlier this month, but few — if any — made it to the Oakland Fire Department.

Oakland Fire Chief Teresa Deloach Reed said Tuesday there are no city records showing her department receiving concerns about the building , which former residents, neighbors and others say was the subject of numerous calls to 911.

“We do not inspect buildings, we inspect businesses,” Reed said during a press conference. “There were no indications this was an active business.”

City administrator Sabrina Landreth, who also is in temporary charge of the Oakland Police Department, said officials are compiling and reviewing police records to determine how many times officers responded to complaints about the warehouse.

The deadliest structure fire in the U.S. in more than a decade broke out during a Dec. 2 late-night dance party in the cluttered warehouse. It killed 36 people. The building had been converted to art studios and illegal living spaces, and former denizens said it was a death trap of piled wood, furniture, snaking electrical cords and only two exits.

Investigators said that they still haven’t determined what started the fire, though they say it didn’t appear to be intentionally set. Instead, investigators have been focusing on electrical appliances plugged into the rear of the building where the fire started.

The electrical system is still part of the analysis of what sparked the fire, said Jill Snyder, the special agent in charge with the U.S. Bureau of Alcohol, Tobacco and Firearms.

The ATF has finished collecting evidence, Snyder said. The Oakland Fire Department will prepare a final report for handover to prosecutors.

Prosecutors have warned murder charges are possible as they determine whether crimes are linked to the blaze.

Alameda County District Attorney Nancy O’Malley said Tuesday the criminal investigation will be “thorough, methodical and calculated.”

City and state officials fielded complaints for years about dangerous conditions, drugs, neglected children, trash, thefts and squabbles at the warehouse, raising questions about why it wasn’t shut down.

There are no records that inspectors from the fire and building departments ever set foot in the warehouse.

The fire chief said the warehouse wasn’t on the department’s list of businesses to inspect because no one ever applied for permits to occupy the building.

Derick Ion Almena, the sometime photographer who rented the warehouse and sublet it to artists, has not responded to emails or calls by The AP to phone numbers associated with him. In a brief interview with NBC’s “Today” show, Alemena said he didn’t attend the Dec. 2 party and that he is sorry. Alemena said he lived at the warehouse with his wife and three young children, though they were staying at a hotel the night the fire broke out.

The warehouse’s owner, Chor Ng, has not responded to emails and calls made by The AP to phone numbers associated with her. The landlord’s daughter, Eva Ng, told The Los Angeles Times that the Ng family didn’t know people were living in the warehouse in violation of city zoning laws.

The blaze was the nation’s most lethal structure fire since 100 people perished in a Rhode Island bar in 2003.

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Associated Press writers Kristen Bender and Ellen Knickmeyer in San Francisco contributed to this report.

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